245P Antitumor-protumor ratio as an important prognostic biomarker in metastatic triple-negative breast cancer: A multicenter cohort study

Triple-negative breast cancer (TNBC) had a higher mortality rate than other BCs. Antitumor–protumor interaction is pivotal in prognoses. This study analyzes antitumor–protumor immune activities and their ratios as prognostic biomarkers in metastatic TNBC (mTNBC). A multicenter cohort study was conducted in seven centers that provide comprehensive cancer treatment. Paraffin block specimens and metastasis data were collected. Expression of CD8, CD163, and PD-L1 and expression of CD4 and FOXP3 were evaluated using immunohistochemistry (IHC) and double-stain IHC, respectively. Cut-off points using the area under the curve (AUC) categorized high- and low-level groups. Kaplan–Meier and log-rank tests were performed to evaluate overall survival (OS). Cox regression was performed for bivariate and multivariate analysis. A scoring system was built using significant variables. In total, 103 de novo mTNBC subjects were analyzed. High levels of CD4, CD8, CD4/FOXP3, CD8/FOXP3, and CD8/CD163 were significantly associated with a higher one-year OS. Low levels of CD4, CD8, CD4/FOXP3, CD8/FOXP3, and CD8/CD163 indicated a median OS of 205, 179, 191, 201, and 197 days, respectively; high levels indicated a median OS >365 days. Multivariate analysis showed that CD4/FOXP3 (hazard ratio (HR), 1.857; 95% confidence interval (CI), 1.049–3.288; p=0.034) and CD8/CD163 (HR, 2.089; 95% CI, 1.174–3.717; p=0.012) ratios significantly impacted one-year OS. Analysis of PD-L1 showed insignificant results. A score system for predicting one-year mortality was obtained. Low CD4/FOXP3 or CD8/CD163 ratios scored 1, high level scored 0. Scores of 0, 1, and 2 indicated one-year mortality probabilities of 39.46%, 53.86% and 75.67%, respectively.Table: 245PBiomarkers (Low-level groups)Median survival (days)HR (Hazard ratio)Multivariate p-valueCD42051.4150.393CD81971.6210.128CD4/FOXP31911.8570.034CD8/FOXP32011.4670.295CD8/CD1631972.0890.012 Open table in a new tab High antitumor activity significantly improved the one-year OS in de novo mTNBC patients. A scoring system after external validation is a promising prognostic tool for modifying treatment.